1. Field of the Invention
This invention relates to a minimal access tool, such as for surgery, endoscopy, or other interventions.
2. Background Art
Minimally invasive surgical (MIS) and other minimal access procedures are increasing in frequency and becoming more complex, thus demanding improvements in technology to meet the needs of surgeons. In these procedures, generally thin tools are inserted into the body through ports. Motion input from the user, such as a surgeon, is transferred via the tool to the motion of a manipulator attached to the tool's tip inside the patient's body. This arrangement is used to carry out an externally controlled operation within the body without making large incisions. MIS tools range from simple scissor-like tools to complex robotic systems.
Most traditional tools for use in MIS are mechanical and hand-held, and provide 4 degrees of freedom (DoF) (3 translations and 1 roll rotation) plus grasping, while some newer ones further add up to 2 DoF (pitch, yaw). While these mechanical hand-held tools are inherently capable of force feedback, and the newer tools are capable of enhanced dexterity given their extra two DoF, they present non-intuitive DoF control (input motion to output motion mapping) schemes that limit user's ability to fully exploit the tool's enhanced dexterity capability. With robotic tools, the use of electromechanical actuators to produce motion of the tool tip manipulator takes away the mechanical force feedback. In addition, large size, high cost, and limited large-scale maneuverability also reduce the overall functionality of such robotic systems.
Therefore, most existing multiple DoF tools lack the design characteristics to allow for enhanced dexterity as well as desired functionality in a cost effective, compact package. In particular, multiple DoF tools that allow for wrist-like rotations of the tool tip manipulator are important to meet the needs of modern minimal access and MIS procedures, but are not effective unless comfortable, ergonomic, and intuitive control of these additional DoF are ensured.